The present invention relates to a device for assembling motor-vehicle bodies by spot-welding, comprising:
a welding station, provided with programmable robots having spot-welding heads, PA1 means for feeding motor-vehicle body floor panels in sequence to the welding station, PA1 a pair of locating gates on two opposite sides of the welding station, provided with devices for receiving and supporting elements forming two motor-vehicle body sides which are to be assembled with a respective floor panel, PA1 wherein said locating gates are provided with self-propelled lower carriages, guided on two parallel rails provided on the floor of the welding station, at the two sides thereof, PA1 wherein said gates are movable on said rails between a working position, adjacent to the two sides of the floor panel which is located at the welding station, and a waiting position, spaced longitudinally from the working position, PA1 wherein when said locating gates are in their waiting positions, they are able to receive and support elements forming the sides of a body to be assembled, PA1 wherein when said locating gates are in their working position, they are able to move transversally relative to the longitudinal direction of said rails, coming closer to each other until they reach an operative position immediately adjacent to the floor panel which is located at the welding station, PA1 wherein said locating gates are provided with locating and locking means able to enter into operation when said gates are at their operative position for causing engagement of the elements forming the sides carried by said gates and the floor panel which is located at the welding station with each other, in order to keep them in a proper position for assembling the body, while said robots carry out a number of welding spots, and PA1 means for feeding the assembled body out of the welding station. PA1 said means for feeding the floor panels to the welding station and said means for feeding the assembled bodies out of the welding station are constituted by an overhead conveyor, which is at an elevated position relative to the welding station, and comprising a line portion upstream of the welding station for conveying the floor panels to be assembled, and a line portion downstream of the welding station for conveying the assembled bodies, as well as by a lifting device provided with vertically movable supporting means, for picking up a floor panel from the overhead conveyor line and lowering said floor panel down to the welding station, where it is taken by locating and supporting means provided at the welding station, and for lifting afterwards the assembled body from the welding station up to the overhead conveyor line, PA1 said programmable robots are able to carry out firstly a number of welding spots for framing the body, while the body is being locked by the locating gates, and later on a number of welding spots for completing welding of the body, while the locating gates have already been disengaged from the body and have returned to their waiting position, at which they are able to receive the elements forming the sides of a new body, simultaneously with the execution of said welding spots for completing the body which is at the welding station.
A device for assembling motor-vehicle bodies by spot-welding, having the above indicated features, has been proposed in Italian patent application No. TO96A000817 filed on Oct. 8, 1996 and still secret at the filing date of the present application.